Automated enforcement is used in some jurisdictions to reduce red-light running and speeding. . . . Speed cameras, also called photo radar or automated speed enforcement, operate similarly, recording a vehicle’s speed using radar or other instrumentation and taking a photograph of the vehicle when it exceeds a threshold limit. NHTSA and FHWA have released speed camera enforcement program and operational guides with information on problem identification and program planning, communications strategies, obtaining community and other stakeholder support, processing of violations, and program evaluation ([NHTSA, 2008i]; [FHWA and NHTSA, 2008]). (UNC Highway Safety Research Center, 2011, p. 3-12)
History
The first automated speed limit–enforcement program was implemented in Paradise Valley, Arizona, in 1987 (Retting, 2010). Since then, at least 92 jurisdictions (state and local) have adopted automatic enforcement, although speed cameras are not as widely used as red-light cameras. Several jurisdictions, including the State of Maryland and Cincinnati, Ohio, that previously adopted speed cameras have repealed or considered repealing or restricting their speed-camera laws, following legal challenges, as well as negative sentiment among constituents (“Speed Camera Repeal Effort an Easy Sell,” 2009).
Use
“Speed cameras have been used in 12 States and the District of Columbia ([IIHS, 2010a]), but not all of these programs may be active at present” (UNC Highway Safety Research Center, 2011, p. 3-12) because local jurisdictions generally contract private firms for the operation of these systems and contract durations vary. For example, the Arizona Department of Public Safety allowed a two-year freeway speed-camera program contract to expire in 2010 (city cameras continue to remain in effect). A compilation of industry listings shows that 92 local governments and authorities had active automated speed cameras as of September 2011, but exact numbers are difficult to obtain because of the lack of federal regulatory oversight (Madsen and Baxandall, 2011). “Speed cameras also are used extensively in other countries” (UNC Highway Safety Research Center, 2011, p. 3-12), such as Australia, Norway, and the United Kingdom (Peden et al., 2004). “Information on States’ laws authorizing or restricting use of automated enforcement is provided by the GHSA ([2014c]) and by IIHS ([2014b])” (UNC Highway Safety Research Center, 2011, p. 3-12).
Effectiveness
Speed cameras can reduce crashes substantially. [Decina, Thomas, et al., 2007] reviewed 13 safety impact studies of automated speed enforcement internationally, including one study from a United States jurisdiction. The best-controlled studies suggest injury crash reductions are likely to be in the range of 20 to 25 percent at conspicuous, fixed camera sites. Covert, mobile enforcement programs also result in significant crash reductions area-wide ([L. Thomas et al., 2008]). Prior reviewers also concluded that, although the quality of evidence was not high, speed cameras and speed detection technologies are effective at reducing traffic crashes and injuries ([Pilkington and Kinra, 2005]; [C. Wilson, Willis, Hendrikz, and Bellamy, 2006]). Recent crash-based studies from the United States have reported positive safety benefits through crash and speed reductions from mobile camera enforcement on 14 urban arterials in Charlotte, NC ([Cunningham, Hummer, and Moon, 2008]), and from fixed camera enforcement on an urban Arizona freeway ([Shin, Washington, and van Schalkwyk, 2009]). (UNC Highway Safety Research Center, 2011, pp. 3-12–3-13)
The Shin et al. (2009) study examined effects of a fixed camera enforcement program applied to a 6.5-mile urban freeway section through Scottsdale, Arizona. The speed limit on the enforced freeway is 65 mph; the enforcement trigger was set to 76 mph. Total target crashes [crashes during nonpeak periods that are materially affected by camera enforcement] were reduced by an estimated 44 to 54 percent, injury crashes by 28 to 48 percent, and property damage only crashes by 46 to 56 percent during the nine month program period. (The program was temporarily suspended, then reactivated; future evaluations may elaborate on the results.) Since analyses found low speeding detection rates during peak travel times, the target crashes (speeding-related crashes) were considered to be those that occurred during non-peak flow periods (weekends, holidays, and non-peak weekdays hours). In addition to the crash reductions, average speed was decreased by about 9 mph and speed variance [a measure related to the range of speeds and the amount of variability around the average speed] was also decreased around the enforced zones. (UNC Highway Safety Research Center, 2011, p. 3-13)
[In addition, an] economic analysis suggested that the total estimated safety benefits [including medical, quality of life, and other costs (emergency responders, insurance, wage loss, household work loss, legal fees, and property damage)] were from $16.5 [million] to $17.1 million per year, although other economic impacts were not considered. Another positive finding from this study was that all types of crashes appeared to be reduced, with the possible exception of rear-end crashes, for which effects were non-significant. Thus, there were no obvious trade-offs of decreases in some crash types at the expense of increases in others. The program effects should be considered short-term. There was also very limited examination of spillover effects, including the possibility of traffic or crash diversion to other routes. (UNC Highway Safety Research Center, 2011, p. 3-13)
Pilot project evaluations of speed camera use in the United States have also obtained promising speed reductions from fixed speed cameras on a high-speed, urban freeway in Scottsdale, Arizona ([Retting, Kyrychenko, and McCartt, 2008]), low-speed, school zones in Portland, Oregon (Freedman et al., 2006), and low-speed limit residential streets and school zones in Montgomery County, Maryland ([Retting, Farmer, and McCartt, 2008]). In the latter case, speed reductions attributed to spillover from the automated enforcement program were also observed on unenforced comparison streets ([Retting, Farmer, and McCartt, 2008]). The percentage of speeders was also substantially reduced when police-operated photo radar enforcement vans were present in a work zone on a non-interstate highway in Portland, Oregon, but there was no carry-over when the enforcement was not present (Joerger, 2010). Given that there was no evidence of any accompanying publicity, there was, however, no reason to expect carry-over outside of the enforced periods. Crash and injury outcomes were not evaluated in these studies. (UNC Highway Safety Research Center, 2011, p. 3-13)
Recent Research on Effectiveness
A 2010 update to a 2006 Cochrane systematic review on the effectiveness of speed cameras included an additional nine high-quality studies and maintained the qualitative results from the previous review (C. Wilson, Willis, Hendrikz, Le Brocque, and Bellamy, 2010). The studies reported reductions in average speed of between 1 percent and 15 percent and reductions in the proportion of speeding vehicles of between 14 percent and 65 percent, relative to similar controls. Speed cameras also reduced total crashes 8 percent to 49 percent and fatal and serious-injury crashes 11 percent to 44 percent, in studies that compared pre- and postcrash data collected near camera sites.
Measuring Effectiveness
Effectiveness of speed cameras is typically measured in outcomes related to speed or collisions. Speed outcomes include reductions in average speed, distribution or variance of speed, or percentage of vehicles speeding. Studies varied in their definition of speeding—some included any vehicle exceeding the posted limit, while others considered vehicles only at or above a threshold above the legal limit, such as 15 mph above the limit. Collision outcomes include the number or rate of crashes stratified by severity (property damage only, injury, or fatality). It is not clear what the appropriate surveillance area is, but common areas range from 0.15 to 1.25 miles from the camera locations.
Costs
Costs will be based on equipment choices, operational and administrative characteristics of the program, and arrangements with contractors. Cameras may be purchased, leased, or installed and maintained by contractors for a negotiated fee ([FHWA and NHTSA, 2008]). In 2001, red-light cameras cost about $50,000 to $60,000 to purchase and $25,000 to install. Monthly operating costs were about $5,000 [per camera system] ([Maccubbin, Staples, and Salwin, 2001]). . . . Speed camera costs probably are similar [to those for red-light cameras, but speed cameras are single-purpose—that is, speed cameras cannot be used for red-light enforcement]. [G. Chen, 2005] provides an extensive analysis of the costs and benefits of the British Columbia, Canada speed camera program. [Gains et al., 2004] reported on costs and benefits and program factors of a cost-recovery program used in the U.K. (UNC Highway Safety Research Center, 2011, pp. 3-13–3-14)
Time to Implement
“Once any necessary legislation is enacted, automated enforcement programs generally require 4 to 6 months to plan, publicize, and implement” (UNC Highway Safety Research Center, 2011, p. 3-14).
Other Issues
Laws
Many jurisdictions using automated enforcement are in States with laws authorizing its use. Some States permit automated enforcement without a specific State law. A few States prohibit or restrict some forms of automated enforcement ([GHSA, 2014c]; [IIHS, 2014b] [see Table B.1]). See NCUTLO (2004) for a model automated enforcement law. (UNC Highway Safety Research Center, 2011, p. 3-14)
Public Acceptance
Public surveys typically show strong support for red-light cameras and somewhat weaker support for speed cameras ([IIHS, 2014a]; NHTSA, 2004). Support appears highest in jurisdictions that have implemented red-light or speed cameras. However, efforts to institute automated enforcement often are opposed by people who believe that speed or red-light cameras intrude on individual privacy or are an inappropriate extension of law enforcement authority. They also may be opposed if they are viewed as revenue generators rather than methods for improving safety. Per citation payment arrangements to private contractors should be avoided to reduce the appearance of conflicts of interest (FHWA, 2005). (UNC Highway Safety Research Center, 2011, p. 3-14)
Although a recent report by the U.S. Public Interest Research Group (U.S. PIRG) (Madsen and Baxandall, 2011), a federation of state Public Interest Research Groups (PIRGs), noted that such practices have become less common, but contracts may still link revenue to citations through a predetermined proportion of revenue; a variable proportion of revenues based on timeliness of fine collection, quotas, and volume-based payments; and surcharges from alternatives, such as traffic school.
Australian researchers discussed how Australia and the United Kingdom have dealt with the opponents of and controversies associated with speed cameras and expanded programs at the same time ([Delaney, Diamantopoulou, and Cameron, 2003]; [Delaney, Ward, et al., 2005]). (UNC Highway Safety Research Center, 2011, p. 3-14)
Legality
Where cases have been brought, state courts have “consistently supported the constitutionality of automated enforcement” (UNC Highway Safety Research Center, 2011, p. 3-14).
Covert Versus Overt Enforcement
Covert, mobile speed camera enforcement programs may provide a more generalized deterrent effect and may have the added benefit that drivers are less likely to know precisely when and where cameras are operating. Drivers may therefore be less likely to adapt to speed cameras by taking alternate routes or speeding up after passing cameras, but data are lacking to confirm this idea ([L. Thomas et al., 2008]). Public acceptance [of speed cameras] may be somewhat harder to gain with more covert forms of enforcement ([FHWA and NHTSA, 2008]). Fixed, or signed, conspicuous mobile enforcement may also be more noticeable and achieve more rapid site-specific speed and crash reductions. However, the use of general signs in jurisdictions with automated enforcement (not at specifically enforced zones), media, and other program publicity about the need for speed enforcement may help to overcome the idea that covert enforcement is unfair, and promote the perception that enforcement is widespread, enhancing deterrence effects. Based on lessons learned abroad, a mix of conspicuous and covert forms of enforcement may be most effective. The recent operational guidelines outline other considerations of overt and covert speed enforcement and signing strategies ([FHWA and NHTSA, 2008]). (UNC Highway Safety Research Center, 2011, p. 3-14)
Halo Effects
C. Wilson, Willis, Hendrikz, Le Brocque, and Bellamy, 2010, refer to the time halo and the distance halo. Time halo refers to the effect on speed after the enforcement has ended, and distance halo refers to the effect on speed at and around an active enforcement site.
More research is needed to shed light on spillover effects (positive or negative) of automated speed enforcement programs of varying characteristics. While fixed cameras may yield more dramatic decreases in crashes at the treated sites (which, however, are often sites with high crash frequencies) than mobile enforcement, there is little reason to expect that there would be a significant positive spillover effect. In fact some studies have detected crash migration [an increase in crashes at adjacent non-enforced sites] related to conspicuous, fixed camera enforcement ([Decina, Thomas, et al., 2007]). There is also a possibility of negative spillover [in the form of crash migration] resulting from mobile camera enforcement, but signing and random deployment practices may reduce that possibility ([L. Thomas et al., 2008]). (UNC Highway Safety Research Center, 2011, pp. 3-14–3-15)
No comments:
Post a Comment